The invention relates to a piston pump for delivering hydraulic fluid for motor vehicle brake systems with an antilocking device.
In a known piston pump of this type (WO 95/168859 A1), to reduce manufacturing costs, the guide bore for the pump piston is embodied directly in the pump body, i.e. without the use of a separate pump cylinder inserted into the pump body for the sliding guidance of the pump piston. To seal the pump piston in relation to the inner wall of the guide bore, a high pressure seal is provided, embodied as an annular seal comprised of polytetrafluoroethylene (PTFE), which is received on a step of the pump piston and in the axial direction, rests against the radial shoulder of the step. The omission of the pump cylinder that acts as a slide bush makes it necessary to take steps to prevent a damage or intense abrasion of the slide bush against the pump piston and of the sealing face against the annular seal in the longer term, particularly when the pump body is made out of aluminum in order to reduce costs. A measure of this kind, for example, is the anodization of the pump body.